uc.c

   1 #include <ctype.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include "vi.h"
   6
   7 #define LEN(a)          (sizeof(a) / sizeof((a)[0]))
   8
   9 /* return the length of a utf-8 character */
  10 int uc_len(char *s)
  11 {
  12         int c = (unsigned char) s[0];
  13         if (c > 0 && c <= 0x7f)
  14                 return 1;
  15         if (c >= 0xfc)
  16                 return 6;
  17         if (c >= 0xf8)
  18                 return 5;
  19         if (c >= 0xf0)
  20                 return 4;
  21         if (c >= 0xe0)
  22                 return 3;
  23         if (c >= 0xc0)
  24                 return 2;
  25         return c != 0;
  26 }
  27
  28 /* the number of utf-8 characters in s */
  29 int uc_slen(char *s)
  30 {
  31         char *e = s + strlen(s);
  32         int i;
  33         for (i = 0; s < e; i++)
  34                 s += uc_len(s);
  35         return i;
  36 }
  37
  38 /* the unicode codepoint of the given utf-8 character */
  39 int uc_code(char *s)
  40 {
  41         int result;
  42         int l = uc_len(s);
  43         if (l <= 1)
  44                 return (unsigned char) *s;
  45         result = (0x3f >> --l) & (unsigned char) *s++;
  46         while (l--)
  47                 result = (result << 6) | ((unsigned char) *s++ & 0x3f);
  48         return result;
  49 }
  50
  51 /* find the beginning of the character at s[i] */
  52 char *uc_beg(char *beg, char *s)
  53 {
  54         while (s > beg && (((unsigned char) *s) & 0xc0) == 0x80)
  55                 s--;
  56         return s;
  57 }
  58
  59 /* find the end of the character at s[i] */
  60 char *uc_end(char *beg, char *s)
  61 {
  62         if (!*s || !((unsigned char) *s & 0x80))
  63                 return s;
  64         if (((unsigned char) *s & 0xc0) == 0xc0)
  65                 s++;
  66         while (((unsigned char) *s & 0xc0) == 0x80)
  67                 s++;
  68         return s - 1;
  69 }
  70
  71 /* return a pointer to the character following s */
  72 char *uc_next(char *s)
  73 {
  74         s = uc_end(s, s);
  75         return *s ? s + 1 : s;
  76 }
  77
  78 int uc_wid(char *s)
  79 {
  80         return 1;
  81 }
  82
  83 /* allocate and return an array for the characters in s */
  84 char **uc_chop(char *s, int *n)
  85 {
  86         char **chrs;
  87         int i;
  88         *n = uc_slen(s);
  89         chrs = malloc((*n + 1) * sizeof(chrs[0]));
  90         for (i = 0; i < *n + 1; i++) {
  91                 chrs[i] = s;
  92                 s = uc_next(s);
  93         }
  94         return chrs;
  95 }
  96
  97 char *uc_chr(char *s, int off)
  98 {
  99         int i = 0;
 100         while (s && *s) {
 101                 if (i++ == off)
 102                         return s;
 103                 s = uc_next(s);
 104         }
 105         return s && (off < 0 || i == off) ? s : "";
 106 }
 107
 108 /* the number of characters between s and s + off*/
 109 int uc_off(char *s, int off)
 110 {
 111         char *e = s + off;
 112         int i;
 113         for (i = 0; s < e && *s; i++)
 114                 s = uc_next(s);
 115         return i;
 116 }
 117
 118 char *uc_sub(char *s, int beg, int end)
 119 {
 120         char *sbeg = uc_chr(s, beg);
 121         char *send = uc_chr(s, end);
 122         int len = sbeg && send && sbeg <= send ? send - sbeg : 0;
 123         char *r = malloc(len + 1);
 124         memcpy(r, sbeg, len);
 125         r[len] = '\0';
 126         return r;
 127 }
 128
 129 char *uc_dup(char *s)
 130 {
 131         char *r = malloc(strlen(s) + 1);
 132         return r ? strcpy(r, s) : NULL;
 133 }
 134
 135 int uc_isspace(char *s)
 136 {
 137         int c = s ? (unsigned char) *s : 0;
 138         return c <= 0x7f && isspace(c);
 139 }
 140
 141 int uc_isprint(char *s)
 142 {
 143         int c = s ? (unsigned char) *s : 0;
 144         return c > 0x7f || isprint(c);
 145 }
 146
 147 int uc_isalpha(char *s)
 148 {
 149         int c = s ? (unsigned char) *s : 0;
 150         return c <= 0x7f && isalpha(c);
 151 }
 152
 153 int uc_isdigit(char *s)
 154 {
 155         int c = s ? (unsigned char) *s : 0;
 156         return c <= 0x7f && isdigit(c);
 157 }
 158
 159 int uc_kind(char *c)
 160 {
 161         if (uc_isspace(c))
 162                 return 0;
 163         if (uc_isalpha(c) || uc_isdigit(c) || c[0] == '_')
 164                 return 1;
 165         return 2;
 166 }
 167
 168 #define UC_R2L(ch)      (((ch) & 0xff00) == 0x0600 || \
 169                         ((ch) & 0xfffc) == 0x200c || \
 170                         ((ch) & 0xff00) == 0xfb00 || \
 171                         ((ch) & 0xff00) == 0xfc00 || \
 172                         ((ch) & 0xff00) == 0xfe00)
 173
 174 /* sorted list of characters that can be shaped */
 175 static struct achar {
 176         unsigned c;             /* utf-8 code */
 177         unsigned s;             /* single form */
 178         unsigned i;             /* initial form */
 179         unsigned m;             /* medial form */
 180         unsigned f;             /* final form */
 181 } achars[] = {
 182         {0x0621, 0xfe80},                               /* hamza */
 183         {0x0622, 0xfe81, 0, 0, 0xfe82},                 /* alef madda */
 184         {0x0623, 0xfe83, 0, 0, 0xfe84},                 /* alef hamza above */
 185         {0x0624, 0xfe85, 0, 0, 0xfe86},                 /* waw hamza */
 186         {0x0625, 0xfe87, 0, 0, 0xfe88},                 /* alef hamza below */
 187         {0x0626, 0xfe89, 0xfe8b, 0xfe8c, 0xfe8a},       /* yeh hamza */
 188         {0x0627, 0xfe8d, 0, 0, 0xfe8e},                 /* alef */
 189         {0x0628, 0xfe8f, 0xfe91, 0xfe92, 0xfe90},       /* beh */
 190         {0x0629, 0xfe93, 0, 0, 0xfe94},                 /* teh marbuta */
 191         {0x062a, 0xfe95, 0xfe97, 0xfe98, 0xfe96},       /* teh */
 192         {0x062b, 0xfe99, 0xfe9b, 0xfe9c, 0xfe9a},       /* theh */
 193         {0x062c, 0xfe9d, 0xfe9f, 0xfea0, 0xfe9e},       /* jeem */
 194         {0x062d, 0xfea1, 0xfea3, 0xfea4, 0xfea2},       /* hah */
 195         {0x062e, 0xfea5, 0xfea7, 0xfea8, 0xfea6},       /* khah */
 196         {0x062f, 0xfea9, 0, 0, 0xfeaa},                 /* dal */
 197         {0x0630, 0xfeab, 0, 0, 0xfeac},                 /* thal */
 198         {0x0631, 0xfead, 0, 0, 0xfeae},                 /* reh */
 199         {0x0632, 0xfeaf, 0, 0, 0xfeb0},                 /* zain */
 200         {0x0633, 0xfeb1, 0xfeb3, 0xfeb4, 0xfeb2},       /* seen */
 201         {0x0634, 0xfeb5, 0xfeb7, 0xfeb8, 0xfeb6},       /* sheen */
 202         {0x0635, 0xfeb9, 0xfebb, 0xfebc, 0xfeba},       /* sad */
 203         {0x0636, 0xfebd, 0xfebf, 0xfec0, 0xfebe},       /* dad */
 204         {0x0637, 0xfec1, 0xfec3, 0xfec4, 0xfec2},       /* tah */
 205         {0x0638, 0xfec5, 0xfec7, 0xfec8, 0xfec6},       /* zah */
 206         {0x0639, 0xfec9, 0xfecb, 0xfecc, 0xfeca},       /* ain */
 207         {0x063a, 0xfecd, 0xfecf, 0xfed0, 0xfece},       /* ghain */
 208         {0x0640, 0x640, 0x640, 0x640},                  /* tatweel */
 209         {0x0641, 0xfed1, 0xfed3, 0xfed4, 0xfed2},       /* feh */
 210         {0x0642, 0xfed5, 0xfed7, 0xfed8, 0xfed6},       /* qaf */
 211         {0x0643, 0xfed9, 0xfedb, 0xfedc, 0xfeda},       /* kaf */
 212         {0x0644, 0xfedd, 0xfedf, 0xfee0, 0xfede},       /* lam */
 213         {0x0645, 0xfee1, 0xfee3, 0xfee4, 0xfee2},       /* meem */
 214         {0x0646, 0xfee5, 0xfee7, 0xfee8, 0xfee6},       /* noon */
 215         {0x0647, 0xfee9, 0xfeeb, 0xfeec, 0xfeea},       /* heh */
 216         {0x0648, 0xfeed, 0, 0, 0xfeee},                 /* waw */
 217         {0x0649, 0xfeef, 0, 0, 0xfef0},                 /* alef maksura */
 218         {0x064a, 0xfef1, 0xfef3, 0xfef4, 0xfef2},       /* yeh */
 219         {0x067e, 0xfb56, 0xfb58, 0xfb59, 0xfb57},       /* peh */
 220         {0x0686, 0xfb7a, 0xfb7c, 0xfb7d, 0xfb7b},       /* tcheh */
 221         {0x0698, 0xfb8a, 0, 0, 0xfb8b},                 /* jeh */
 222         {0x06a9, 0xfb8e, 0xfb90, 0xfb91, 0xfb8f},       /* fkaf */
 223         {0x06af, 0xfb92, 0xfb94, 0xfb95, 0xfb93},       /* gaf */
 224         {0x06cc, 0xfbfc, 0xfbfe, 0xfbff, 0xfbfd},       /* fyeh */
 225         {0x200c},                                       /* ZWNJ */
 226         {0x200d, 0, 0x200d, 0x200d},                    /* ZWJ */
 227 };
 228
 229 static struct achar *find_achar(int c)
 230 {
 231         int h, m, l;
 232         h = LEN(achars);
 233         l = 0;
 234         /* using binary search to find c */
 235         while (l < h) {
 236                 m = (h + l) >> 1;
 237                 if (achars[m].c == c)
 238                         return &achars[m];
 239                 if (c < achars[m].c)
 240                         h = m;
 241                 else
 242                         l = m + 1;
 243         }
 244         return NULL;
 245 }
 246
 247 static int can_join(int c1, int c2)
 248 {
 249         struct achar *a1 = find_achar(c1);
 250         struct achar *a2 = find_achar(c2);
 251         return a1 && a2 && (a1->i || a1->m) && (a2->f || a2->m);
 252 }
 253
 254 static int uc_cshape(int cur, int prev, int next)
 255 {
 256         int c = cur;
 257         int join_prev, join_next;
 258         struct achar *ac = find_achar(c);
 259         if (!ac)                /* ignore non-Arabic characters */
 260                 return c;
 261         join_prev = can_join(prev, c);
 262         join_next = can_join(c, next);
 263         if (join_prev && join_next)
 264                 c = ac->m;
 265         if (join_prev && !join_next)
 266                 c = ac->f;
 267         if (!join_prev && join_next)
 268                 c = ac->i;
 269         if (!join_prev && !join_next)
 270                 c = ac->c;      /* some fonts do not have a glyph for ac->s */
 271         return c ? c : cur;
 272 }
 273
 274 /*
 275  * return nonzero for Arabic combining characters
 276  *
 277  * The standard Arabic diacritics:
 278  * + 0x064b: fathatan
 279  * + 0x064c: dammatan
 280  * + 0x064d: kasratan
 281  * + 0x064e: fatha
 282  * + 0x064f: damma
 283  * + 0x0650: kasra
 284  * + 0x0651: shadda
 285  * + 0x0652: sukun
 286  * + 0x0653: madda above
 287  * + 0x0654: hamza above
 288  * + 0x0655: hamza below
 289  * + 0x0670: superscript alef
 290  */
 291 static int uc_comb(int c)
 292 {
 293         return (c >= 0x064b && c <= 0x0655) ||          /* the standard diacritics */
 294                 (c >= 0xfc5e && c <= 0xfc63) ||         /* shadda ligatures */
 295                 c == 0x0670;                            /* superscript alef */
 296 }
 297
 298 static void uc_cput(char *d, int c)
 299 {
 300         int l = 0;
 301         if (c > 0xffff) {
 302                 *d++ = 0xf0 | (c >> 18);
 303                 l = 3;
 304         } else if (c > 0x7ff) {
 305                 *d++ = 0xe0 | (c >> 12);
 306                 l = 2;
 307         } else if (c > 0x7f) {
 308                 *d++ = 0xc0 | (c >> 6);
 309                 l = 1;
 310         } else {
 311                 *d++ = c;
 312         }
 313         while (l--)
 314                 *d++ = 0x80 | ((c >> (l * 6)) & 0x3f);
 315         *d = '\0';
 316 }
 317
 318 /* shape the given arabic character; returns a static buffer */
 319 char *uc_shape(char *beg, char *s)
 320 {
 321         static char out[16];
 322         char *r;
 323         int prev = 0;
 324         int next = 0;
 325         int curr = uc_code(s);
 326         if (!curr || !UC_R2L(curr)) {
 327                 uc_cput(out, curr);
 328                 return out;
 329         }
 330         r = s;
 331         while (r > beg) {
 332                 r = uc_beg(beg, r - 1);
 333                 if (!uc_comb(uc_code(r))) {
 334                         prev = uc_code(r);
 335                         break;
 336                 }
 337         }
 338         r = s;
 339         while (*r) {
 340                 r = uc_next(r);
 341                 if (!uc_comb(uc_code(r))) {
 342                         next = uc_code(r);
 343                         break;
 344                 }
 345         }
 346         uc_cput(out, uc_cshape(curr, prev, next));
 347         return out;
 348 }